[fixed]toSColor() not accurate

[Virion]

I realize currently Irrlicht's SColorf to SColor conversion isn't very accurate

example:

I set an SColor's RGB values to 1, 2, 3 (small value to test out accuracy) and it saves 3 of these values into f32 when saving scene, resulting 0.003922, 0.007843, 0.011765

When I load back the scene using loadScene(), I get 1, 1, 3 instead of 1, 2, 3... I have to grab those RGB values to fill in the GUI form for my level editor and I want it to be precise. I realized that if I use Irrlicht's built-in toSColor() function it doesn't round off the decimals.

I've tested it by manually *255 for each of the f32 value
0.003922*255 = 1.00011
0.007843*255 = 1.999965
0.011765*255 = 3.000075

should be 1, 2, 3 but it gives me 1, 1, 3...

[Lonesome Ducky]

It's a precision error I believe, irrlicht can't be more accurate than the floating point that holds the values. EDIT: Oh are you talking about the rounding down instead of up?

[CuteAlien]

Thanks, nice catch. I suppose using core::round_ instead might be the better option (a little slower...). Maybe the same in getInterpolated and in SColorHSL::toRGB1. Although I'm not sure if it's worth the speed-hit in getInterpolated (then again getInterpolated also seems to waste some time on clamping a value). Also not sure right now if we should fix this for 1.7.2 or 1.8 (is this is a bug or does that count as changing behavior?).

Anyway - I think we should change it, but I'm waiting a day or two in case anyone else has some feedback.

[Halifax]

The speed increase would be minimal, but I don't think that core::round_ should be used. The behavior of a cast from a positive floating-point value to an unsigned integer is truncation i.e. floor. So I think an explicit addition of 0.5 should be added. core::round_ adds 0.5 to value, casts it to a 64-bit unsigned integer, performs a floor on the value, and then finally casts it to a 32-bit floating-point value.

[hybrid]

The proper call would probably be round32. Using library calls is always better than doing it manually in the code.

[Virion]

for now i can do it manually for the values that I get from getShadowColor(), getAmbientLight() etc. but I realize that getFog only returns u32 values and no f32 so I couldn't convert it. maybe i'll just wait for the update.

[CuteAlien]

Ok, I have used round32 and changed it in the 1.7 svn branch.